1. Field of the Invention
The invention relates to coupling lines for use in a YIG band-pass filter or a YIG oscillator and a method for producing such coupling lines, suitable for use in a YIG band-pass filter or a YIG oscillator.
2. Related Technology
YIG band-pass filters or YIG oscillators have at least one resonator, which is preferably constructed as spherical and made from an yttrium iron garnet (YIG). The resonator action is conveyed by means of coupling lines which must be constructed and arranged in such a way that the center point of the resonator and the center point of the bend radius of a coupling line match exactly.
A YIG band-pass filter with appropriately constructed coupling lines is known from U.S. Pat. No. 4,480,238, for example. The variable frequency YIG band-pass filter here has a basic body, comprising slits for accommodating insulated chips which have a conductive coating on one edge, which acts as coupling lines. Furthermore, filter chambers are provided to accommodate the YIG elements. The chips are inserted in the slits via the YIG elements in such a way that the YIG elements are arranged in indentations in the edges provided with the conductive coating. The YIG elements and the chips are fixed in permanent positions.
A disadvantage of the YIG band-pass filter known from the aforementioned document is, in particular, the complicated production of the chips forming the coupling lines. The insulator acting as support must first be appropriately formed and then provided with the conducting coating. This is complicated and liable to rejects, as the coating is susceptible to damage, owing to its small layer thickness.